The present invention relates to an aqueous dispersion for chemical mechanical polishing (hereunder referred to simply as xe2x80x9caqueous dispersionxe2x80x9d) that is useful for polishing of copper during manufacture of semiconductor devices. More specifically, it relates to an aqueous dispersion for chemical mechanical polishing that can be suitably used in the wiring formation steps for semiconductor devices that require combinations of fine wiring of about 0.1 xcexcm to thick wiring of about 100 xcexcm, such as in DRAMs, high-speed logic LSIs and the like.
High densification of semiconductor devices has led to advances in micronization of formed wirings in recent years. The damascene method is well known as a technique allowing further micronization of wiring. This method involves embedding a wiring material in a groove or the like formed in an insulating material, and then removing the excess wiring material by chemical mechanical polishing to form the desired wiring. High-speed polishing is desired for this method in order to achieve improved yields in the polishing step.
When polishing an initial excess film [thickness X (xc3x85)] with the wiring material embedded in the groove at a polishing rate V (xc3x85/min), the intended polishing should be achievable in the time X/V (min), but in actual semiconductor device manufacturing steps, wiring material left at sections other than the groove is also removed, such that overpolishing is carried out for a time exceeding X/V (min). Here, overpolishing of the wiring sections can result in formation of pit shapes. Such pit-shaped wiring is known as xe2x80x9cerosionxe2x80x9d,and is undesirable since it lowers yields of the semiconductor device.
In light of these circumstances, it has been a goal to achieve an aqueous dispersion for chemical mechanical polishing that can polish wiring materials at high speed in chemical mechanical polishing steps while also producing no erosion when overpolishing is conducted. However, an aqueous dispersion for chemical mechanical polishing having such function has not yet been proposed.
It is an object of the present invention to overcome these problems by providing an aqueous dispersion for chemical mechanical polishing that realizes high polishing speed in chemical mechanical polishing steps and can be used for polishing of copper while minimizing erosion and erosion rates in the course of overpolishing.
The present invention is as follows.
1. An aqueous dispersion for chemical mechanical polishing used for polishing of copper characterized by containing (A) a compound having a heterocycle, (B) a surfactant and (C) an oxidizing agent, wherein the weight ratio of the (A) and (B) is 1:10 to 1:0.03.
2. An aqueous dispersion for chemical mechanical polishing used for polishing of copper according to 1 above, wherein the (A) compound having the heterocycle is a compound having a condensed ring composed of a benzene ring or naphthalene ring and a heteropentacycle or heterohexacycle with at least one nitrogen atom.
3. An aqueous dispersion for chemical mechanical polishing used for polishing of copper according to 2 above, wherein the compound having the condensed ring includes a structure selected from among quinoline, isoquinoline, benzotriazole, benzimidazole, indole, isoindole, quinazoline, cinnoline, quinoxaline, phthalazine and acridine.
4. An aqueous dispersion for chemical mechanical polishing used for polishing of copper according to 3 above, wherein the compound having the condensed ring is at least one selected from among quinaldic acid, benzotriazole and benzimidazole.
5. An aqueous dispersion for chemical mechanical polishing used for polishing of copper according to 4 above, wherein the (B) surfactant is an anionic surfactant.
6. An aqueous dispersion for chemical mechanical polishing used for polishing of copper according to 5 above, wherein said anionic surfactant is a sulfonic acid salt.
7. An aqueous dispersion for chemical mechanical polishing used for polishing of copper according to 6 above, wherein said sulfonic acid salt is at least one selected from ammonium dodecylbenzenesulfonate and potassium dodecylbenzenesulfonate.
8. An aqueous dispersion for chemical mechanical polishing used for polishing of copper according to 5 above, wherein said (C) oxidizing agent is at least one selected from among ammonium persulfate, potassium persulfate and hydrogen peroxide.
9. An aqueous dispersion for chemical mechanical polishing used for polishing of copper according to 2 above, which further contains (D) an abrasive.
10. An aqueous dispersion for chemical mechanical polishing used for polishing of copper according to 9 above, wherein said (D) abrasive is a silica particle and/or an organic/inorganic composite particle.
11. An aqueous dispersion for chemical mechanical polishing used for polishing of copper according to 10 above, wherein said compound having said condensed ring includes a structure selected from among quinoline, isoquinoline, benzotriazole, benzimidazole, indole, isoindole, quinazoline, cinnoline, quinoxaline, phthalazine and acridine.
12. An aqueous dispersion for chemical mechanical polishing used for polishing of copper according to 11 above, wherein said compound having said condensed ring is at least one selected from among quinaldic acid, benzotriazole and benzimidazole.
13. An aqueous dispersion for chemical mechanical polishing used for polishing of copper according to 12 above, wherein said (B) surfactant is an anionic surfactant.
14. An aqueous dispersion for chemical mechanical polishing used for polishing of copper according to 13 above, wherein said anionic surfactant is a sulfonic acid salt.
15. An aqueous dispersion for chemical mechanical polishing used for polishing of copper according to 14 above, wherein said sulfonic acid salt is at least one selected from ammonium dodecylbenzenesulfonate and potassium dodecylbenzenesulfonate.
16. An aqueous dispersion for chemical mechanical polishing used for polishing of copper according to 13 above, wherein said (C) oxidizing agent is at least one selected from among ammonium persulfate, potassium persulfate and hydrogen peroxide.
According to the invention it is possible to obtain an aqueous dispersion for chemical mechanical polishing with a high polishing speed for copper and a low overpolishing margin, which is useful for polishing of copper for multilayer wiring in the manufacture of semiconductor devices.